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// SPDX-License-Identifier: GPL-2.0-only
/*
* Routines for doing kexec-based kdump.
*
* Copyright (C) 2005, IBM Corp.
*
* Created by: Michael Ellerman
*/
#undef DEBUG
#include <linux/crash_dump.h>
#include <linux/io.h>
#include <linux/memblock.h>
#include <asm/code-patching.h>
#include <asm/kdump.h>
#include <asm/prom.h>
#include <asm/firmware.h>
#include <linux/uaccess.h>
#include <asm/rtas.h>
#include <asm/inst.h>
#ifdef DEBUG
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif
#ifndef CONFIG_NONSTATIC_KERNEL
void __init reserve_kdump_trampoline(void)
{
memblock_reserve(0, KDUMP_RESERVE_LIMIT);
}
static void __init create_trampoline(unsigned long addr)
{
struct ppc_inst *p = (struct ppc_inst *)addr;
/* The maximum range of a single instruction branch, is the current
* instruction's address + (32 MB - 4) bytes. For the trampoline we
* need to branch to current address + 32 MB. So we insert a nop at
* the trampoline address, then the next instruction (+ 4 bytes)
* does a branch to (32 MB - 4). The net effect is that when we
* branch to "addr" we jump to ("addr" + 32 MB). Although it requires
* two instructions it doesn't require any registers.
*/
patch_instruction(p, ppc_inst(PPC_INST_NOP));
patch_branch((void *)p + 4, addr + PHYSICAL_START, 0);
}
void __init setup_kdump_trampoline(void)
{
unsigned long i;
DBG(" -> setup_kdump_trampoline()\n");
for (i = KDUMP_TRAMPOLINE_START; i < KDUMP_TRAMPOLINE_END; i += 8) {
create_trampoline(i);
}
#ifdef CONFIG_PPC_PSERIES
create_trampoline(__pa(system_reset_fwnmi) - PHYSICAL_START);
create_trampoline(__pa(machine_check_fwnmi) - PHYSICAL_START);
#endif /* CONFIG_PPC_PSERIES */
DBG(" <- setup_kdump_trampoline()\n");
}
#endif /* CONFIG_NONSTATIC_KERNEL */
static size_t copy_oldmem_vaddr(void *vaddr, char *buf, size_t csize,
unsigned long offset, int userbuf)
{
if (userbuf) {
if (copy_to_user((char __user *)buf, (vaddr + offset), csize))
return -EFAULT;
} else
memcpy(buf, (vaddr + offset), csize);
return csize;
}
/**
* copy_oldmem_page - copy one page from "oldmem"
* @pfn: page frame number to be copied
* @buf: target memory address for the copy; this can be in kernel address
* space or user address space (see @userbuf)
* @csize: number of bytes to copy
* @offset: offset in bytes into the page (based on pfn) to begin the copy
* @userbuf: if set, @buf is in user address space, use copy_to_user(),
* otherwise @buf is in kernel address space, use memcpy().
*
* Copy a page from "oldmem". For this page, there is no pte mapped
* in the current kernel. We stitch up a pte, similar to kmap_atomic.
*/
ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
size_t csize, unsigned long offset, int userbuf)
{
void *vaddr;
phys_addr_t paddr;
if (!csize)
return 0;
csize = min_t(size_t, csize, PAGE_SIZE);
paddr = pfn << PAGE_SHIFT;
if (memblock_is_region_memory(paddr, csize)) {
vaddr = __va(paddr);
csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf);
} else {
vaddr = ioremap_cache(paddr, PAGE_SIZE);
csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf);
iounmap(vaddr);
}
return csize;
}
#ifdef CONFIG_PPC_RTAS
/*
* The crashkernel region will almost always overlap the RTAS region, so
* we have to be careful when shrinking the crashkernel region.
*/
void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
{
unsigned long addr;
const __be32 *basep, *sizep;
unsigned int rtas_start = 0, rtas_end = 0;
basep = of_get_property(rtas.dev, "linux,rtas-base", NULL);
sizep = of_get_property(rtas.dev, "rtas-size", NULL);
if (basep && sizep) {
rtas_start = be32_to_cpup(basep);
rtas_end = rtas_start + be32_to_cpup(sizep);
}
for (addr = begin; addr < end; addr += PAGE_SIZE) {
/* Does this page overlap with the RTAS region? */
if (addr <= rtas_end && ((addr + PAGE_SIZE) > rtas_start))
continue;
free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
}
}
#endif
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